Solution
Given,
Diameter of 15th ring (D15) = 0.590 cm,
Diameter of 5th ring (D5) = 60 cm = 0.6 m,
Wavelength of light (λ) = 5580 Å = 5580 x 10^-8 cm
Radius of curvature (R) = ?,
m = 15,
n = 5
We have,
\(R=\frac{D_m^2-D_n^2}{4\lambda\left(m-n\right)}\)
= \(\frac{D_{15}^2-D_5^2}{4\lambda\left(15-5\right)}\)
= 100 cm
= 1 m
Therefore, the radius of curvature of the plano-convex lens is 1m.